Such sensor devices can be used for pipe constructions, for example, generally or specifically for handling devices or industrial robots or for prostheses.
By way of example, a sensor device for measuring a torque transversely with respect to the longitudinal pipe direction of the pipe is known from the company Otto Bock Healthcare GmbH in Duderstadt. In this case, the pipe is used for the connection between a controllable artificial knee joint and a prosthetic foot. The pipe can be connected to the knee joint by means of a clamp arranged on the knee joint. In this case, the prosthetic foot has what is known as an alignment adaptor to which the pipe can be firmly coupled by means of an adaptor connection, connected thereto, using alignment screws and can be aligned within certain limits. The adaptor connection has a pipe extension piece which is integrally formed on the adaptor connection, wherein the pipe has its end facing the adaptor connection pushed over the pipe extension piece and cemented thereto. In this case, the pipe extension piece and the adaptor connection form a measuring element which can be used to introduce the axial force and the torque into the alignment adaptor and to measure them using strain gauges arranged on the pipe extension piece.
The known pipe extension piece comprises, in principle, a cylindrical extension which is integrally formed on the adaptor connection and which has a perforation transversely with respect to its longitudinal axis and has its front side which faces away from the adaptor connection connected to the base area of a pot-shaped end of the extension piece via two integrally formed web-shaped bars which are opposite one another. The two webs form a sensor region with a respective measuring point having four strain gauges arranged in a bridge circuit. Both the cylindrical extension and the pot-shaped extension have their generated surface cemented to the pipe wall of the pipe.
A drawback in this context is that firstly the measuring element with its pipe extension piece is of relatively complicated and hence costly design and that secondly the demarcation of the axial force from the disturbance loads and the torques to be measured is problematical.
In addition, EP 1 559 384 B1 discloses a sensor device or a torque sensor for measuring a torque which is designed as a sensor structure forming a virtual axis of rotation outside of the sensor and which is arranged directly below the knee joint. In this case, the torque sensor or the measuring element has a multijoint structure with elastically deformable joints.
A drawback in this case is that the measuring element is of relatively complex design and takes up installation space which may already be occupied by fundamental functional elements.
In addition, DE 10 2005 051 495 A1 discloses a sensor arrangement for measuring forces and torques in which the measuring element is in the form of part of an alignment adaptor.
A drawback in this case is that the alignment adaptor is of relative voluminous and complex design.